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[flightgear.git] / docs-mini / README.effects

diff --git a/docs-mini/README.effects b/docs-mini/README.effects
index 550163f29d9de3c4fa2eddf70c9f8b581e3964a8..0e2814e7c28d9b00373f796315a48c70cb06e7c3 100644 (file)
--- a/docs-mini/README.effects
+++ b/docs-mini/README.effects
@@ -35,6 +35,7 @@ and, or, equal, less, less-equal
 glversion - returns the version number of OpenGL
 extension-supported - returns true if an OpenGL extension is supported
 property - returns the boolean value of a property
+float-property - returns the float value of a property, useful inside equal, less or less-equal nodes
 shader-language - returns the version of GLSL supported, or 0 if there is none.
 
 The proper way to test whether to enable a shader-based technique is:
@@ -48,6 +49,23 @@ The proper way to test whether to enable a shader-based technique is:
          </and>
        </predicate>
 
+There is also a property set by the user to indicate what is the level 
+of quality desired. This level of quality can be checked in the predicate
+like this :
+    <predicate>
+      <and>
+        <property>/sim/rendering/shader-effects</property>
+       <less-equal>
+         <value type="float">2.0</value>
+         <float-property>/sim/rendering/quality-level</float-property>
+       </less-equal>
+       <!-- other predicate conditions -->
+      </and>
+    </predicate>
+    
+The range of /sim/rendering/quality-level is [0..5]
+ * 2.0 is the threshold for relief mapping effects,
+ * 4.0 is the threshold for geometry shader usage.
 
 A technique can consist of several passes. A pass is basically an Open
 Scene Graph StateSet. Ultimately all OpenGL and OSG modes and state
@@ -174,6 +192,15 @@ texture-unit - has several child properties:
                        wrap-s
                        wrap-t
                        wrap-r
+                       mipmap-control - controls how the mipmap levels are computed.
+                       Each color channel can be computed with different functions
+                       among average, sum, product, min and max. For example :
+                                       <function-r>average</function-r>
+                                       <function-a>min</function-a>
+                               function-r - function for red
+                               function-g - function for green
+                               function-b - function for blue
+                               function-a - function for alpha
                The following built-in types are supported:
                        white - 1 pixel white texture
                        noise - a 3d noise texture